What are the components of blood?
All blood contains the same basic components:
red blood cells that carry oxygen
white blood cells that fight infection
platelets that help blood clot
plasma, the liquid part of blood
But not everyone has the same blood type.
What is blood type?
Blood type helps prevent transfusion reactions. Red blood cells have markers on their surface that identify the type of cell. These markers (also called antigens) are proteins and sugars that are used to identify the blood cells that belong to our body.
The two main blood types are ABO and Rh.
The ABO blood system has four main types.
Type A: This blood type has a marker called A.
Group B: This blood group has a marker called B.
Type AB: This blood type has markers A and B.
Group O: This blood group does not have A or B markers.
Blood is classified as “Rh positive” (meaning no Rh factor) or “Rh negative” (no Rh factor).
Therefore, there can be eight blood groups:
Oh negative. This blood type does not have A or B markers and does not have the Rh factor.
Oh positive. This blood type does not have A or B markers, but the Rh factor. O-positive blood is one of the two most common blood types (the other being A-positive).
Negative. This blood type has only A.
Positive. This blood group has the A marker and the Rh factor, but no B marker. Along with O-positive, it is one of the two most common blood groups.
B is negative. This blood type has only B.
B is positive. This blood type has B and Rh factor but not A.
AB is negative. The blood group of this group has markers A and B, but no Rh factor.
AB is positive. There are three types of markers for this blood group – A, B and Rh factor.
The presence of one (or none) of these markers does not make a person’s blood healthy or strong. Just genetic differences, like green eyes instead of blue, straight hair instead of curly.
Why is blood type important?
Immunity is the body’s defense against invaders. It can identify the antigen as self or non-self. For a safe blood transfusion, a person’s immune system must recognize the donor’s cells as matching their own. If no match is found, the cell is deleted.
The immune system produces proteins called antibodies to protect the body when foreign cells invade the body. Depending on your blood type, your immune system produces antibodies that react to other blood types.
If the patient receives the wrong blood type, the antibodies immediately begin to destroy the invading cells. Such an aggressive reaction of the whole body can lead to fever, chills and low blood pressure. This can lead to disruption of vital body systems such as breathing and kidneys.
Here’s an example of how blood group antibodies work.
Let’s say your blood type is A. Because your blood contains the A marker, it makes B antibodies.
If B markers (found in blood type B or AB) enter your body, your A immune system will activate against them.
This means that only people with A and O blood types and B and AB blood types can receive a blood transfusion.
Likewise, if you have type B blood, your body will produce type A antibodies. Therefore, a person with blood group B can receive a blood transfusion from a person with blood group B or O, but not from a person with blood group A or AB.
For people with blood group AB or O, things are a little different:
If you have markers A and B on the surface of your cells (blood type AB), your body does not have to deal with their presence.
This means that a person with AB blood can receive a blood transfusion from someone with A, B, AB, or O blood.
But if you have type O blood, your red blood cells don’t have A or B markers. So:
Your body will have A and B antibodies, so it will feel the need to protect itself from A, B, and AB blood.
A person with O blood can only receive an O blood transfusion.
Can teenagers donate blood?
Blood transfusion is one of the most common life-saving surgeries performed in hospitals. Therefore, there is a constant need for blood donors. One blood donation can save three lives.
About 15% of blood donors are high school or college students. Contact your local blood center for assistance. This is one way to become an everyday superhero and save lives!